Well, yeah, thats a possibility--oil on the starter. But-usually the oil doesn't get into the starter assembly, because the starter is well sealed. The main thing keeping a little engine from starting is a dead or low charge on the battery. No wave of the magic wand will make it start! (I know--I already tried that. And, the other thing is having a clean carburetor! Also a clean fuel filter is good.
As for me---i have a magic wand that i pass back and forth across the engine area, and eventually it will make the engine start, and run! ;0)